Tunable upconverter mixer with image rejection
First Claim
1. An upconverter with image rejection capabilities, comprising:
- a. a mixer circuit having inputs for receiving a signal to be upconverted and an oscillator signal to be mixed with the signal to be upconverted, the mixer generates a mixer output signal at a desired sideband frequency and an image signal at an image frequency; and
b. a mixer tuned load circuit coupled to the mixer circuit that resonates and passes signals in a desired passband corresponding to the mixer output signal at the desired sideband frequency, and attenuates signals in an attenuation band that includes the image signal at the undesired image frequency;
c. a pre-amplifier coupled to the output of the mixer circuit to increase the power of the mixer output signal, wherein the pre-amplifier outputs a pre-amplified signal; and
d. a pre-amplifier tuned load circuit coupled to the output of the pre-amplifier to resonate and pass signals in the desired passband and, which attenuates signals in the attenuation band.
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Accused Products
Abstract
Tunable upconversion mixers that have a controllable passband response and provide substantial image rejection, making costly post-mixing filtering at least optional, if not unnecessary for many applications. A single mixer is able to support several frequency bands (and/or be accurately tuned within one frequency band) by means of varying the capacitance in a tunable load circuit for the mixer circuit. The tunable mixer comprises a mixer circuit having inputs for receiving a signal to be upconverted and an oscillator signal to be mixed with the signal to be upconverted. The mixer generates a mixer output signal at a desired sideband frequency and an image signal at an image frequency. A tunable load circuit is coupled to the mixer circuit and responsive to a control signal to resonate and pass signals in a desired passband corresponding to the mixer output signal at the desired sideband frequency, and which attenuates signals in an attenuation band that includes the image signal at the undesired image frequency.
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Citations
28 Claims
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1. An upconverter with image rejection capabilities, comprising:
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a. a mixer circuit having inputs for receiving a signal to be upconverted and an oscillator signal to be mixed with the signal to be upconverted, the mixer generates a mixer output signal at a desired sideband frequency and an image signal at an image frequency; and
b. a mixer tuned load circuit coupled to the mixer circuit that resonates and passes signals in a desired passband corresponding to the mixer output signal at the desired sideband frequency, and attenuates signals in an attenuation band that includes the image signal at the undesired image frequency;
c. a pre-amplifier coupled to the output of the mixer circuit to increase the power of the mixer output signal, wherein the pre-amplifier outputs a pre-amplified signal; and
d. a pre-amplifier tuned load circuit coupled to the output of the pre-amplifier to resonate and pass signals in the desired passband and, which attenuates signals in the attenuation band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A radio transmitter comprising at least first and second transmitter paths each coupled to an associated antenna to process a signal for substantially simultaneous transmission, each of the first and second transmitter paths comprising:
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e. a tunable upconversion mixer that receives as input a baseband or intermediate frequency signal to be upconverted, a local oscillator signal and a tuning control signal, and which upconverts the baseband or intermediate frequency signal to a frequency based on a frequency of the local oscillator signal and in response to the tuning control signal, resonates to pass signals in a desired passband corresponding to a desired sideband frequency, and which attenuates signals in an attenuation band that includes an image signal at an undesired image frequency, and outputting an upconverted signal;
f. at least one power amplifier coupled to the output of the tunable upconversion mixer to amplify the upconverted signal and couple an amplified signal to an associated antenna;
c. a pre-amplifier coupled to the output of the tunable upconversion mixer to increase the power of a mixer output signal output by the tunable upconversion mixer, wherein the pre-amplifier outputs a pre-amplified signal; and
g. a pre-amplifier tunable load circuit coupled to the output of the pre-amplifier and responsive to a control signal to resonate and pass signals in the desired passband, and which attenuates signals in the attenuation band, an output of the pre-amplifier coupled to the at least one power amplifier. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification